The present invention relates generally to devices, systems, and methods for supporting and aligning patients with instruments and/or for analyzing ocular images. Exemplary embodiments of the present invention provide patient alignment between a support structure, such as a chin rest, chair, bed, or table, and a diagnostic instrument, such as a wavefront measurement device, in which the instrument can be moved into alignment with the patient. Other embodiments provide mechanisms for positioning the head and/or body of a patient to align the patient with an instrument during surgery.
Laser eye surgical procedures typically employ ultraviolet or infrared lasers to remove a microscopic layer of stromal tissue from the cornea to alter the cornea's refractive properties. Excimer laser systems generally use argon and fluorine gas to create a non-thermal laser light which can break molecular bonds in a process known as photoablation. Such systems result in the photodecomposition of the corneal tissue, but generally do not cause significant thermal damage to adjacent and underlying tissues of the eye. The photoablation removes the stromal tissue to change the shape or contour of the cornea and can be used to correct myopia (near-sightedness), hyperopia (far-sightedness), astigmatism, high-order aberrations, and the like.
Existing diagnostic systems can be used to measure optical errors of the eye and define a correction to eye. Many existing diagnostic measurement systems support the head of the patient with a chin rest and move the instrument into alignment while the head of the patient is supported with the chin rest. To align the patient with the diagnostic instrument, the instrument operator may adjust the height of the instrument, the separation distance from the instrument to the eye, and the lateral position of the instrument relative to the eye. In some instances, the patient may move while the patient is supported, such that alignment can be difficult in some instances.
Existing laser eye surgery systems have generally included an operator interface for use by the laser system operator in setting up, controlling, monitoring, and generally directing the laser treatment of the patient's eyes. Accurate photoablation of corneal tissues benefits from precise alignment between the eye and the therapeutic laser beam transmitted from the laser system. Many laser eye surgical alignment systems have a patient support that comprises a seat or bed so that the patient is treated while seated, while lying down, or while reclined in a supine position. To align the patient with the laser beam delivery optics, the system operator generally positions the seat or bed into alignment with the laser system. A particularly advantageous user interface and patient support system is described in U.S. patent application Ser. No. 10/226,867, entitled “Improved Interface for Laser Eye Surgery” as filed on Aug. 20, 2002, the full disclosure of which is incorporated herein by reference. Embodiments of that advantageous system may make use of a contoured patient treatment chair to help position a patient into nominal alignment with the laser, allowing the system operator to make fine adjustments using the system interface. As the system can be moved quickly to the nominal alignment for treatment of the left or right eyes, this improved interface system provides significant advantages in ease of use, overall procedure speed, and alignment accuracy. Another patient support system is described in U.S. patent application Ser. No. 11/335,177, as filed on Jan. 18, 2006, and entitled “Compression Head Pillow and Neck Angle Adjustment Mechanism for Refractive Laser Surgery and the Like”, the full disclosure of which is incorporated herein by reference. Embodiments of that system may allow both the height of the patient's head and the angle of the patient's neck to be established independently, and/or may inhibit movement or deflection of the head of the patient from an aligned position.
While known patient support and alignment systems have allowed a large number of patients to benefit from the advantages of diagnostic measurements and laser eye surgery, still further improvements would be desirable. For example, it would be advantageous to more accurately position the patient into alignment with diagnostic instrument and/or laser system. It would also be advantageous to accommodate the wide range of patient physiologies, ideally without decreasing the speed or increasing the complexity of the alignment procedure. Preferably, these benefits would be provided without decreasing the system operator's access to the patient. At least some of these potential advantages may be realized by the systems, devices, and methods described herein below.